Felipe Massa once again topped the timesheets at Valencia. However, ignoring the Brazilian, who is driving the 2004 Ferrari, the 2006 cars are making clear progress.

Today, as has been the case throughout this week's test, the bitterly cold weather had a negative affect, with drivers completing relatively few laps until just before midday. At the time of writing, there are even predictions of snow for Friday.

Massa, at the wheel of V8 powered F2004, was joined by Michael Schumacher, who drove the newly launched 248. The German continued with the development work begun on Tuesday at Mugello, completing 78 laps, while the Brazilian worked on a tyre and engine development programme.

Of the 2006 cars, Rubens Barrichello was quickest, 0.391s down on Massa, but only 0.004s up on Giancarlo Fisichella in the new Renault. The Brazilian was partnered by Jenson Button, who finished fifth quickest, just 0.378s down.

Once they were able to go out for some serious running around 11.00am, Rubens and Jenson continued to work on the general chassis set-up and development of the two brand new chassis.

Anthony Davidson will take over from Jenson tomorrow for the final day of the test.

Despite the early cold, both Renault drivers completed extensive tyre programmes for Michelin throughout the day. For Fernando Alonso, this took the form of a Grand Prix simulation during the morning followed by medium-distance runs in the afternoon, all of which were completed without incident.

Fisichella's day was disrupted by two stoppages on track, the first when a problem with an engine ancillary caused him to spin, while a mechanical problem in the late afternoon curtailed his running. Nevertheless, he completed 68 laps, setting the third fastest time.

"The weather meant we had another slow start to the day," said Christian Silk, "but when the drivers began their programme, we had another very productive day. Giancarlo was slightly hampered by two technical incidents, but we expect that at this time of year, early in the car's development.

"Both drivers are happy with the car's performance, and we made very good progress on the tyres today," he added. "It was also pleasing to see Fernando complete our first race simulation this morning, without problems."

Fourth quickest was Nick Heidfeld, who was joined, once again, by Robert Kubica. The German worked on set-ups, and also tested tyre compounds, while the Pole made a number of practice starts, in addition to learning procedures and working on set-ups. He also completed a tyre test programme.

"Overall, the test in Barcelona was very positive for our team," said Willy Rampf. "The reliability of the F1.06 is already at a good level, which enabled us to complete over 1500 kilometres with the new car during the four days.

"We were able to collect a lot of valuable data and learned more about the set-up of the car. In addition, I am very satisfied with the Robert's debut for our team. Over two days, he didn't make the smallest error, and was able to improve constantly. On top of that he is also able to give valuable feedback to the engineers."

Red Bull appears to be making progress, David Coulthard finishing seventh quickest as the team appears to be getting over the overheating problem which has afflicted the RBR2 in recent tests. A Red Bull source told Pitpass that the team is confident that the problem will be resolved soon, adding that the car has more pace but that the team doesn't to push too hard at this stage.